The Department of Science and Technology Region 10 has evaluated the efficiency of a local invention to disinfect facemasks.
Engr. Elpidio M. Paras, chief executive of Parasat Cable TV and an inventor, developed the Parazapp UV Disinfection Cabinet—a portable and low-cost disinfecting equipment that is composed of locally-available materials such as stainless steel cabinet, timer system and UV-C germicidal lamps.
Paras teamed up with DOST-X through the latter’s Regional Standards and Testing Laboratories for the initial evaluation of the germicidal properties and initial determination of the optimal exposure time for the Parazapp.
The RSTL team treated N95 facemask samples with Escherichia Coli (E. coli) bacteria and subjected the samples to different exposure times from 30 seconds to five minutes. The Parazapp achieved 83 percent to 97 percent reduction of E. coli populations when used for five minutes.
Through statistical methods, the team also estimated the proper exposure time needed to achieve higher reduction levels. At least 24 minutes of exposure inside the Parazapp may be needed to achieve a 99.99 percent reduction of E. coli populations in the masks, and at least 38 minutes may be needed to achieve 99.9999 percent reduction.
Disinfection through UV radiation, however, has its limitations. UV disinfection is most effective for flat, non-porous surfaces and transparent substances. PPEs that are multi-layered and made of opaque materials may not achieve proper disinfection. UV radiation also poses threats of skin and eye damage to operators when exposed without protection.
The US Environmental Protection Agency requires at least 99.9999 percent reduction of bacteria to qualify as disinfection. This shows that the Parazapp has the potential for disinfection of E. coli bacteria and other microbes in masks.
With the current rise of COVID-19, the Parazapp can also be potentially used to disinfect viruses in PPEs and other materials.
But his would require further research and development with appropriate methods, testing equipment, and facilities, according to the DOST.